build.ps1: update import paths to "go.etcd.io/etcd"
build.ps1: update import paths to "go.etcd.io/etcd"

Signed-off-by: Gyuho Lee <0fbd30d364d71722b926950b451cecd97b54fc29@amazon.com>

dannysauer/etcd,ajityagaty/etcd,vimalk78/etcd,etcd-io/etcd,gyuho/etcd,li-ang/etcd,ajityagaty/etcd,mqliang/etcd,joshix/etcd,mkumatag/etcd,coreos/etcd,xiang90/etcd,dannysauer/etcd,ajityagaty/etcd,joshix/etcd,xiang90/etcd,rnaveiras/etcd,mqliang/etcd,vimalk78/etcd,etcd-io/etcd,cockroachdb/etcd,cockroachdb/etcd,mkumatag/etcd,gyuho/etcd,mkumatag/etcd,rnaveiras/etcd,mqliang/etcd,li-ang/etcd,coreos/etcd,etcd-io/etcd,rnaveiras/etcd